Over time, the bearings in your idler pulley get worn out, and eventually it will begin to squeal. A new idler pulley will cost about 22 to 23 bucks at NAPA.

Tools needed: Screw driver, 15 mm wrench and a friend.

You'll want to set the parking brake on your truck, just for safety.

1st, remove your intake tube using a screw driver, and pull it out of the way. There is a connector for a tube that goes to the valve cover, if your like me and cant figure out how the heck this thing comes undone, you can just pull the tube off the valve cover.

2nd, locate your tensioner, its below and between you A/C and idler pulleys. On it is a 15 mm bolt, you'll put your 15 mm wrench on that and turn it as if you were tightening the bolt there. This would release the tension off the belt. This is where your friend comes in and slides the belt off the A/C pulley.

3rd, once the belt is off, you can now begin to remove your Idler pulley. The Bolt is the same size as the tensioner pulley(15 mm), only this time you'll be loosening the bolt.

4th, now that the idler is off, you need to disassemble it. It has a plate washer thing on the back and keeps the bolt in place.
The best way i found to remove it is to stick your screw driver between the teeth of the washer plate thing, and loosen the bolt. Once it has been loosened, the plate washer thing will spin off easily.
Once you got the bolt out, you'll notice it has a bushing on there, leave it in place, stick the bolt and bushing into the new pulley and put the plate washer thingy back on the reverse way you took it off.

5th, Now place you new idler pulley in place, MAKE SURE THE BELT IS BELOW THE PULLEY

6th, once the idler pulley bolt is tight, take your 15 mm wrench and place it back on the tensioner, and have your friend slide the belt back into place as you turn the wrench right, which pulls the tensioner back allowing you to get the belt back into place

Finally, put your intake tube back into place using your screw drive to to tighten down the bands. If your like me and couldn't figure out how that connector worked and just pulled the tube off the valve cover, make sure that is fully placed down into the valve cover.

Now make a quick inspection and go over everything to make sure its all done correctly, all bolt tight, belt on the pulley correctly and everything else. Once that id done go ahead and start your truck up and inspect your idler pulley and belt. If it appears to be coming undone, quickly turn off your truck and start over again and figure out what went wrong.
Don't be afraid to rev up your engine and turn the A/C on, you want to make sure everything is working, you don't want to lose your belt while going down the road.
if everything looks good then you should be set.
Now your done.

This is going to sound dumb but I have a 2.3L 2001. I was told it had an idler pulley and to replace it while I replace my belt and tensioner... Well I got the above pulley but noticed that in my engine bay I do NOT have a tensioner puller that I can locate...